反应详情

To 4-amino-3-methoxyphenylboronic acid pinacol ester (1340 mg, 5.38 mmol) in tetrahydrofuran (20 ml) under a nitrogen atmosphere was added slowly a 2M solution of ethylmagnesium chloride in tetrahydrofuran (2.69 ml, 5.38 mmol) and the resulting solution was heated at reflux for one hour. Methyl 6-methyl-6H-thieno[2,3-b]pyrrole-5-carboxylate (500 mg, 2.56 mmol) was added and the reaction mixture was heated at reflux for 18 hours. The reaction mixture was cooled to room temperature and poured in brine. The mixture was extracted three times with ethyl acetate and the combined organic layers were washed subsequently with water and brine. The organic layer was dried (Na2SO4) and concentrated in vacuo. The residue was purified by column chromatography (silica gel; heptane with gradient of 0 to 50% of ethyl acetate). The product was dissolved in hot dichloromethane and the remaining solids were removed by filtration. The filtrate was concentrated, the residue dissolved in hot dichloromethane and diethylether was added. The formed solids were collected by filtration, washed with diethylether and dried to yield N-(2-methoxy-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)-6-methyl-6H-thieno[2,3-b]pyrrole-5-carboxamide (343 mg).

1. temperaturethe resulting solution was heated
2. temperatureat reflux for one hour
3. temperaturethe reaction mixture was heated
4. temperatureat reflux for 18 hours
5. extractionThe mixture was extracted three times with ethyl acetate
6. washthe combined organic layers were washed subsequently with water and brine
7. dry with materialThe organic layer was dried (Na2SO4)
8. concentrationconcentrated in vacuo
9. customThe residue was purified by column chromatography (silica gel; heptane with gradient of 0 to 50% of ethyl acetate)
10. dissolutionThe product was dissolved in hot dichloromethane
11. customthe remaining solids were removed by filtration
12. concentrationThe filtrate was concentrated
13. dissolutionthe residue dissolved in hot dichloromethane
14. additiondiethylether was added
15. filtrationThe formed solids were collected by filtration
16. washwashed with diethylether
17. customdried